Sheet-metal container



.June v8, 1943. J. MILLS Erm.

' SHEET METAL CONTAINER l Fi1ed` Oct 30. 1941 Patented June 8,. 1943 2,321,403 SHEET-METAL CONTAINER John Mills and Charles W. Lang, Chicago, Ill., assignors to Continental Can Company, Inc., New York, N. Y., a corporation of New York Application October 30, 1941, Serial No. 417,196

2 Claims.

The invention relates to new and useful improvements in sheet metal containers and more particularly to a container wherein the cover end is double seamed to the container body forclosing and sealing the same.

An object of the invention is to provide a sheet metal container of the above type wherein the vertical wall surrounding the depression in the cover end is so shaped as to provide open passages when the cover is partially seated through which passages gases may pass into or out of the container.

A further object of the invention is to provide a container of the above type wherein the depression is of greater depth than the seam which joins the cover to the container body and wherein the vertical wall surrounding the depression is of substantially uniform diameter, closely fitting the inner wa11 of the container body in the region of pressure during double seaming and wherein said vertical wall below said region is provided at spaced intervals with inwardly bent portions forming relatively narrow channels through which gases may pass into or out of the container when the cover end is partially seated.

In the drawing which shows by way of illustration one embodiment of the invention,

Figure 1 is a side elevation with parts broken away of a container embodying the invention with the cover end partially seated.

Figure 2 is a bottom plan view of the closure for the container shown in Figure 1.

Figure 3 is an enlarged sectional view of the container on the line 3--3 of Figure 2.

Figure 4 is an enlarged sectional view of the container on the line 4-4 of Figure 2.

Figure 5 is a view similar to Figure 3 but showing the cover fully seated.

Figure 6 is a view similar to Figure 5 showing the double seam completed which joins the cover end to the container body.

The invention has to do with a sheet metal container in which food products are marketed. It is desirable in connection with many food products to subject the same to treatment after they are placed in the container in which they are to be marketed for rendering the food products sterile. It is also desirable in connection with certain food products to remove air from the headspace of the container and from the product so far as possible so that when the product is sealed in the container it is substantially free from any deteriorating action through contact of the product with oxygen in the air.

The purpose of the invention is to provide a .sheet metal container of the open top type and the free passage of gases into and out of the container. In this type of container, the cover end is provided with a depression surrounded by a vertical wall which must necessarily closely t the inner wall of the container body in the region where the double seam is to be formed so that a chuck used in the seaming operation may be inserted in the .depression and serve as an abutment against which the parts are pressed by the seaming rolls during the seaming operation. It is very desirable that this vertical wall in the region of the seam shall be of uniform diameter in order that a tight seam can be produced during the seaming operation. The present invention has particularly to do with the construction of the cover end so as to provide channels through which gases may pass into or out of the container, which channels are so shaped and disposed as not to interfere with the forming of a tight seam for joining the cover end to the container body. The depression in the cover end is extended down into the container for a limited distance so that there is a portion of the vertical wall surrounding the recess below the region of the double seam. In this portion, vertical channels are formed at spaced intervals by bending the vertical wall inwardly and it is these channels which provide passages for the gases to enter and escape from the container.

Referring more in detail to the drawing, the container as illustrated includes a body portion I which is preferably cylindrical in shape. Said body portion has a bottom end 2 secured thereto by the usual double seam 3. The open end of the container is provided with a ange 4. The containeris closed and sealed by a cover end 5 which is attached to the container body by a double seam indicated at 6 in Figure 6 of the drawing. This isy a usual form of sheet metal container in which food products are marketed and is often referred to as an open top container,

The cover end is provided with a depression 1 'which is surrounded by a vertical wall .8.' The cover also has a portion 9 which extends out over the flange 4 of the can body when the cover is applied thereto and this portion 9 of the cover is rolled with the ange into the double seam 6. A

sealing compound is applied to the channel in' double seam. In the present embodiment of thetainer to a limited distance below the lowermost edge of the finished double seam. The vertical wall of the depression in this region below the double seam is provided with vertical channels I formed by die shaping when the cover end is formed. These depressions, as clearly shown in Figure 2, extend inwardly toward the center of the cover. The depression is of the greatest depth radially of the cover at the lower end thereof and gradually decreases in depth until it merges into the portion of the vertical wall. Except for these depressions in the vertical wall,

.said vertical wall is of substantially uniform diameter and is dimensioned so as to snugly fit the interior of the container body. When the cover is applied so that it is partially seated as shown in Figures 1 and 3, that is with the curled under edge of the cover substantially in line with the ange of the container body, there are open channels through which gases may freely pass into the container or out of the container. When, however, the cover is fully seated as shown in Figure 5, then these passages are closed and the portion of the vertical wall, which is of uniform diameter throughout, is brought into engagement with the can body in the region where the seam is to be formed. A chuck can be placed in this portion of the depression and serve asan abutment against which the seam parts are shaped by the seaming rolls. v

From the above it will be noted that the cover endmay be moved from the position shown in Figures 3 andfi to the position shown in Figure 5 by a pressure exerted lengthwise of the wall of the container and the only restraining force in this full seating of the cover is the frictional contact between the vertical wall surrounding the depression in the can end and the. vertical wall of the container body. This enables the cover flange to be pressed into sealing engagement with the body flange prior to the engagement of the seaming rolls with said yianges for forming the seam and insures a tight seam formation.

The improved container described above is` particularly useful in the packaging of food products which must be subjected to heat treatment for rendering the same sterile and also food products which, when nally sealed in a container. must be free from contact `with the oxygen of the air and which makes it desirable, therefore, to remove all the air possible from the headspace within the container before the container is sealed.

The container is filled with the food product and then the cover is partially seated as shown in Figures 1 and 4. This leaves the channels I0 open for the free passing of gases into and out of the container. One method of treating the food product consists in preheating the product in the container either before or after the cover is partially seated as referred to above. The container is then surrounded with steam under comparatively low pressure which will cause the steam to enter. through the channels and heat the food product where it contacts therewith. The steam pressure is then reduced so that the steam expanding will pass out of the container and carry with it a large proportion of the air inthe headspace of the container. This step of causing steam to enter and move out of the con- A invention, this depression 'l extends into the container bywexpansion may be repeated until the headspace isl fairly cleared of air. The container is then inverted in the presence of surrounding steam under low pressure and without further seating of the cover so that the channels. are open. The steam pressure is increased and steam will enter through these channels passing through the food product. condenslngas it contacts with the food product so that further steam may enter until the. food product is thoroughly contacted with the heating units derived from the steam and the product thus rendered sterile to a large extent. yThe cover is then fully seated and the double seam formed for sealing the container. further processed if found necessary and then cooled and it is ready for the market.

This process which has been referred to in a general Way forms no part of the present invention, butis fully described and claimed in a companion application Serial Number 430,818, filed February 13, 1942.

While it is preferred to form these channels in the vertical wallof the cover so as not to interfere in any way with the double seaming operation which must follow in order to seal the container, it will be understood that the structure embodying the invention may be greatly modified without departing from the spirit of the invention as set forth in the appended claims.

While the wall surrounding the depression in the cover is referred to as vertical, it will be understood that in commercial practice there is a slight angle or taper to this wall so as to facilitate the entering of the chuck into the recess for the seaming operation` and also so as to facilitate the entering of the cover into the container body.

It is also understood that While this improved container is especially adapted for the steam treatment offood products it may also be used in connection with the drawing of a vacuum on the headspace of the container and the relieving of a vacuum by an inert gas.

We claim:

1. A sheet metal container comprising a body portion and cover and adapted to be seamed thereto for closing and sealing the container, said cover end having a central depressed portion surrounded by a vertical wall adapted to fit within the body portion of the container, said vertical wall of the cover end having at spaced intervals inwardly curved portions providing channels through which gases may pass into and out vof the container.

l2. A sheet metal container comprising a body portion and cover end adapted to be seamed thereto for closing and sealing the container, said cover end having a central depressed portion surrounded by a vertical wall adapted to t within the body portion of the container, the upper portion of said vertical wall of the cover end being of substantially uniform diameter throughout and the lower portion of said vertical wall of the cover end having inwardly curved portions forming channels at spaced intervals through which gases may pass into and out of the'container when the vertical wall of the cover end is engaged with the body portion for a part ofits height.

Y JOHN MILLS.

CHARLES W. LANG.-

After the container is sealed, it may be. 

